Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Griffith, W. A. Articles by Cooke, M. L. Search for Related Content GeoRef GeoRef Citation

How Sensitive Are Fault-Slip Rates in the Los Angeles Basin to Tectonic Boundary Conditions?

¹ Department of Geosciences
University of Massachusetts
Amherst, Massachusetts 01003
 (W.A.G.)

² Department of Geosciences
University of Massachusetts
Amherst, Massachusetts 01003
cooke{at}geo.umass.edu
 (M.L.C.)

Correspondence: ^* Present address: Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305. wagrif{at}pangea.stanford.edu

Geodetic studies have produced different interpretations of the relative vertical thickening versus escape tectonics occurring within the Los Angeles basin based on calculated horizontal strain rates ranging from 56 x 10^–9/yr contraction at N36°E to 85 x 10^–9/yr north–south contraction and 60 x 10^–9/yr east–west extension. Three-dimensional forward mechanical models of faults in the Los Angeles basin are used to compare modeled slip rates and slip styles, represented as the rakes of average net slip vectors, under four representative horizontal strain conditions with geologically determined late-Quaternary slip rates and observed slip styles. The comparisons strive to identify the most mechanically viable tectonic boundary conditions for the Los Angeles basin. The three-dimensional fault surfaces used within the mechanical models have been defined by Southern California Earthquake Center (SCEC) workers based on surface geology and subsurface data. The model results suggest that northeast–southwest principal contraction is inappropriate for the Los Angeles basin because this tectonic boundary condition produces left-lateral slip along the Whittier and San Gabriel faults in contrast with abundant geologic evidence of right-lateral slip. Of the four tectonic boundary conditions evaluated, north–south contraction accompanied by either zero or slow east–west contraction gives the lowest mismatch of modeled and observed fault slip style. These results suggest that vertical thickening may be more predominant than escape tectonics in this region.

This article has been cited by other articles:

				M. Radiguet, F. Cotton, I. Manighetti, M. Campillo, and J. Douglas Dependency of Near-Field Ground Motions on the Structural Maturity of the Ruptured Faults Bulletin of the Seismological Society of America, August 1, 2009; 99(4): 2572 - 2581. [Abstract] [Full Text] [PDF]

				S. T. Marshall, M. L. Cooke, and S. E. Owen Effects of Nonplanar Fault Topology and Mechanical Interaction on Fault-Slip Distributions in the Ventura Basin, California Bulletin of the Seismological Society of America, June 1, 2008; 98(3): 1113 - 1127. [Abstract] [Full Text] [PDF]

				A. J. Meigs, M. L. Cooke, and S. T. Marshall Using Vertical Rock Uplift Patterns to Constrain the Three-Dimensional Fault Configuration in the Los Angeles Basin Bulletin of the Seismological Society of America, February 1, 2008; 98(1): 106 - 123. [Abstract] [Full Text] [PDF]

				A. Plesch, J. H. Shaw, C. Benson, W. A. Bryant, S. Carena, M. Cooke, J. Dolan, G. Fuis, E. Gath, L. Grant, et al. Community Fault Model (CFM) for Southern California Bulletin of the Seismological Society of America, December 1, 2007; 97(6): 1793 - 1802. [Abstract] [Full Text] [PDF]